Question

Determine whether the sum to infinity of the following G.P’.s exist. If exists, find it:

`-3, 1, (-1)/3, 1/9`, ...

Answer 1

`-3, 1, (-1)/3, 1/9`, ...

a = – 3, r = `-1/3`

Since, | r | = `|-1/3| < 1`

∴ Sum to infinity exists.

Sum to infinity = `"a"/(1 - "r") = (-3)/(1 - (-1/3)) = -9/4`